The present invention relates to the technical field of equipment which carries out the filtering and removal of solid particles contained in suspension in a liquid.
Such equipment is used in many industrial applications, including for example that of removing chips and impurities from the lubricating and cooling liquid used in machining operations such as grinding, surfacing, etc.
In currently known equipment, designed and constructed in various ways, all the liquid filtered by the equipment is made to circulate through mechanical filters or cloths and the like, which have to be periodically cleaned or removed with the filtered sludge, and the particles which are concentrated in the filter area also have to be removed periodically.
This requires repeated interruptions of the operating cycle, making it necessary to use two pieces of equipment in parallel, operating alternately, if it is desirable to filter continuously the liquid from a machine tool when it is undesirable, or impossible, to interrupt the operation of the machine tool. The total cost of the complete filter equipment is therefore doubled.
Moreover, since the liquid to be filtered is projected under pressure against the filter surfaces, foreign bodies, sometimes of considerable dimensions and mass, sucked up by the liquid circulation pump, frequently strike the filter surfaces violently and damage them.
The inventor of the present invention has devised equipment which overcomes all the above drawbacks, owing to its particular configuration.
In this equipment, not all of the liquid from which particles in suspension have to be removed passes through a filter layer: some of these particles are permitted to settle under their own weight, so that they converge in a lower section of the equipment.
Additionally, some of the liquid which has already been filtered is used for planned continuous cleaning of the filter layer while the equipment is carrying out its work, and therefore the equipment does not have to be stopped.
The aforementioned particles, when they have formed a mass of predetermined size, are transferred by gravity into an additional underlying section, where they are concentrated and from which they are subsequently discharged into a container with filter walls immersed in the vessel into which the liquid to be filtered is directed.
The passage of the particles from one section to the other, and from there towards the said container with filter walls, is achieved by the cyclic opening and reclosing, with appropriate timing, of valves through which, as is explained more fully below, the sections of the equipment communicate with each other and with the said container with filter walls.
Equipment made according to the present invention can therefore be used continuously, without stops.
The object of the present invention is therefore equipment as described in the precharacterizing clause of the attached claim 1, characterized by what is disclosed in the characterizing clause of the said claim.